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bitrex <bitrex@de.lete.earthlink.net>: May 01 11:14AM -0400 Haven't had time to work on this project recently due to illness. I'm back at it.   I'm still trying to figure out the reason that this synthesizer's membrane buttons keep being non-responsive. Again, there's a certain multi-wire header that plugs into the main board where if I tug on it, things function normally. If I let it go slack, the buttons become non-responsive again. I've cleaned all the connections, reflowed the solder joints to the headers but still no luck.   Can anyone suggest a methodical way to isolate where the problem is?   --     ----Android NewsGroup Reader---- http://usenet.sinaapp.com/

bitrex <bitrex@de.lete.earthlink.net>: May 01 11:25AM -0400 > --   > ----Android NewsGroup Reader---- > http://usenet.sinaapp.com/   Connector in question is 67-74 on the mainboard schematic in the following service manual:     http://www.synfo.nl/servicemanuals/Roland/JUNO-2_SERVICE_NOTES.pdf   --     ----Android NewsGroup Reader---- http://usenet.sinaapp.com/

"pfjw@aol.com" <pfjw@aol.com>: May 01 09:26AM -0700 From your description, it is mechanical. Is there a way, using a dental tool or similar that you might test each wire in the loom as it goes into the connector? I expect you will find the problem there.   Peter Wieck Melrose Park, PA

bitrex <bitrex@de.lete.earthlink.net>: May 01 12:49PM -0400 > From your description, it is mechanical. Is there a way, using a dental tool or similar that you might test each wire in the loom as it goes into the connector? I expect you will find the problem there.   > Peter Wieck > Melrose Park, PA   Sure. How would the test procedure go precisely?

Ralph Mowery <rmowery28146@earthlink.net>: Apr 30 01:31PM -0400 In article <fmmck-785AB7.12474930042016@46.sub-75-242-165.myvzw.com>, fmmck@aol.com says... > lead-free. It may work better if you use a temperature-controlled iron, > capable of higher temperatures than your old iron.   > Fred   Ok Fred, thanks for explaing the 'amalgamates' part. Looks like I will be getting some of the lead free solder. I know the old gold plated RF power transistors gave a lot of problems due to the gold plating of the leads, so guess the lead free boards are doing something similar.   I do have a couple of temperature controlled irons. Also bought one of the hot air gun and soldering pencil stations. Just an inexpensive one for about $ 65 off Ebay. Seems to work well on the regular leaded SMD boards. I have been running the irons up much higher to match the lead free boards.   I have been looking at a lot of the Youtube vids about the SMD soldering and they make it look easy. The boards with the tin/lead solder I have been practicing on usually turn out very well, not so much for the lead free stuff. I do have one small tube of solder that has some silver in it but not sure what else. I need to look it up on the internet and see what it is actually made of. It is some from some samples we got when I was working and no one ever used. The tube does not state the makeup, just thatit has some silver in it.

Jon Elson <elson@pico-systems.com>: Apr 30 01:00PM -0500 Ralph Mowery wrote:     > As it is just for my own use at home I am not worried about the legal > Rohs part. OK, just for your own use, you can do repairs with PbSn solder on assemblies made originally with Pb free. I do this all the time, never had a problem.   You can also, in most cases, do repairs on gear that was made with PbSn solder using SAC305. This does require higher temperatures, but when hand soldering one lead at a time, usually there's no harm.   Jon

Jon Elson <elson@pico-systems.com>: Apr 30 01:06PM -0500 Fred McKenzie wrote:     > While tin-lead-copper solder may help, it would be better to use > lead-free. It may work better if you use a temperature-controlled iron, > capable of higher temperatures than your old iron. Actually, if it amalgamates, you are fine. That essentially means it has made an alloy. Pbf component leads usually do NOT have silver on them, just Tin. Now, GOLD is a problem, a certain percent of gold dissolved into a solder joint can cause brittle structures that fracture under thermal or mechanical stress. They call this intermetallics. But, I've never heard of this with silver. I've done tons of boards with SMDs using PbSn solder, and had no trouble with it. One time ONLY, I got talked into trying gold flash plating on the circuit boards, and had HUGE problems with joints that never flowed, or became brittle. The fix was, desolder, lift the lead, scrape the pad down to bare copper, tin the pad, fold the lead back down and solder. UGGGH! Still gives me nightmares!   Jon

Ralph Mowery <rmowery28146@earthlink.net>: Apr 30 03:33PM -0400 In article <uYWdnX3VN86PabnKnZ2dnUU7-aXNnZ2d@giganews.com>, elson@pico- systems.com says... > pad down to bare copper, tin the pad, fold the lead back down and solder. > UGGGH! Still gives me nightmares!   > Jon   I have ran into the gold problem. Only "simple" cure I know of is to just scrape it to the base material. I never gave the solder any other thought before just use the 60/40 or beter if around 63/37 and rosin flux, but now with that lead free stuff comming in and components having to be made to the Rohs standards it is time to do some asking about the mechanics of it. Seems there are about half a dozen or more mixes now without the lead. There is one other problem I have seen , not with solder, but tin plated items. The tin "whiskers'. Probably will be a problem with the tin/silver and no lead solder. I have read that the military and space agencies still use the tin/lead to not have that problem.   I know I have to use a lot more heat on the irons on that lead free stuff.

"pfjw@aol.com" <pfjw@aol.com>: Apr 30 01:58PM -0700 "Amalgamates" *Does Not* mean that an alloy has been formed. An Amalgam is essentially a solid colloid whereby the *separate* properties of the components makes a mixture that does not behave as either. The best example of this that is easily understood is Dental Amalgam, which is a mixture of silver, tin, copper and zinc, indium and other materials *as a powder* mixed 1:1 with mercury. The mix is pressed into place, whereupon the mercury is displaced and the rest of the mixture hardens. But, it is NOT an alloy. The various components partially dissolve in the mercury and bind to each other as a result. Kinda-sorta like sticky bits of candy would bind to each other if made wet. But, the individual bits of candy never dissolve entirely, and except at the direct interface, could never be described as an alloy. Or, if you must, somewhat like concrete. The components, sand, gravel, water, and cement *cure* (NOT dry) into an amalgam - but they are NOT an alloy.   This is an obscure point, but important in this context. The potential for a non-conductive oxide to form is real as each component of the amalgam remains discrete in its behavior at the chemical level.   The reason that gold is used is that it is more resistant than any other of the noble metals to 'dissolving' into anything, forming an oxide or otherwise degrading. If it is attacked by something, that something will be quite toxic or dangerous in its own right. Those compounds would include chlorine, mercury, cyanide and reactants of same. Gold often does not solder well, true, but that depends much on how how it is alloyed and its purity. 24 karat (pure) gold tends to solder quite easily, if gotten hot enough, but is also very expensive, very soft and for those reasons seldom used. 10 karat gold - the lowest that can still be called 'gold' solders badly unless very high silver-content solder is used, and typically requires a flame. Silver Brazing would be a better description.   Gold is seldom used in soldered components as there is no reason to do so. The only real reason for gold (as it is a poor conductor relative to silver or copper) is its resistance to corrosion on contact-type connectors - jacks, plugs and switches. Soldering *to* a gold-flashed lug or pad is asking for trouble for all sorts of reasons, some obvious, some not so much.   This is basic high-school chemistry - at least when I was in school.   Peter Wieck Melrose Park, PA

"Ian Field" <gangprobing.alien@ntlworld.com>: Apr 30 10:23PM +0100 "Ralph Mowery" <rmowery28146@earthlink.net> wrote in message news:MPG.318e8d38c906088989694@news.east.earthlink.net...   > I am in the US and just doing my own repairs and building.   > Do I need to use any of the lead free solder to repair the boards that > were made usign the lead free solder?   Within the EU; hobby use and repairing originally lead solder equipment is among the exemptions.   Never bothered swotting up on the laws elsewhere, but I think America and Asia comply with RoHS purely so they can export to the EU.   RoHS certification is expensive enough, but certification guaranteeing that cross contamination can't happen in a manufacturing plant that uses both processes, is much more costly - its much cheaper to impose blanket compliance with RoHS, even for goods that don't have to comply.   Mixing them depends on individual compositions - visual appearance of the finished joint is a good indication whether you got away with it.

Ralph Mowery <rmowery28146@earthlink.net>: Apr 30 05:52PM -0400 In article <a6c4d91d-e647-4d3f-9e76-5890eeeca3fe@googlegroups.com>, pfjw@aol.com says...   > The reason that gold is used is that it is more resistant than any other of the noble metals to 'dissolving' into anything, forming an oxide or otherwise degrading. If it is attacked by something, that something will be quite toxic or dangerous in its own right. Those compounds would include chlorine, mercury, cyanide and reactants of same. Gold often does not solder well, true, but that depends much on how how it is alloyed and its purity. 24 karat (pure) gold tends to solder quite easily, if gotten hot enough, but is also very expensive, very soft and for those reasons seldom used. 10 karat gold - the lowest that can still be called 'gold' solders badly unless very high silver-content solder is used, and typically requires a flame. Silver Brazing would be a better description.   > Gold is seldom used in soldered components as there is no reason to do so. The only real reason for gold (as it is a poor conductor relative to silver or copper) is its resistance to corrosion on contact-type connectors - jacks, plugs and switches. Soldering *to* a gold-flashed lug or pad is asking for trouble for all sorts of reasons, some obvious, some not so much.   I know gold is used in contacts because it is resistant to oxidation. They really found that out when computers and memory chips were put together with the tin contacts instead of gold. I have a ham radio repeater made by GE that has some cards in it with the tin edge connectors. About once or twice a year I have to pull them out and give them a good cleaning. The low level audio stages seem to be the worse and I have rewired the circuits to byapss those weak points. What I never did understand is why most of the RF power transistors seem to have gold leads. Most are soldered in and that solder joint often goes bad for the reason you stated. Then you have to scrape off the gold and remove the old solder and put fresh solder on.

MJC <gravity@mjcoon.plus.com>: Apr 30 10:53PM +0100 In article <a6c4d91d-e647-4d3f-9e76-5890eeeca3fe@googlegroups.com>, pfjw@aol.com says... > something will be quite toxic or dangerous in its own right. Those > compounds would include chlorine, mercury, cyanide and reactants of > same.   I think I have mentioned "purple plague" here before. https://en.wikipedia.org/wiki/Gold-aluminium_intermetallic. I learnt about it decades ago when working on experimental conducting films.   I thought that gold was tricky to solder precisely because it did tend to dissolve unless the solder was already loaded with gold.   Mike.

Jon Elson <elson@pico-systems.com>: Apr 30 05:23PM -0500 Ralph Mowery wrote:       > There is one other problem I have seen , not with solder, but tin plated > items. The tin "whiskers'. Probably will be a problem with the > tin/silver and no lead solder. Pure tin solder, if not processed hot enough to anneal the Tin, can get REAL bad. Part of the reason for the tin/silver solder is to reduce the whisker formation, and it seems to work. I had some Xilinx chips which had pure tin lead plating, and I was processing them at PbSn temperatures, and the LEADS, not the solder joints, had whiskers at the bends in the leads, as this is where the stressed tin was. Xilinx suggested hotter soldering temps.   Jon

"pfjw@aol.com" <pfjw@aol.com>: May 01 07:43AM -0700 On Saturday, April 30, 2016 at 6:00:05 PM UTC-4, MJC wrote:   > I thought that gold was tricky to solder precisely because it did tend > to dissolve unless the solder was already loaded with gold.   Not really. Gold is also somewhat lubricious - and things flow well on it. BUT, they do not STICK well to it. Solder will flow and appear to be nice and tight, until it peels off like cheap tape. But it takes more than heat to cause gold to dissolve.   Peter Wieck Melrose Park, PA

Jon Elson <jmelson@wustl.edu>: Apr 26 02:56PM -0500 Danny DiAmico wrote:       > The ground straps seem to have good contact, so, I think it's > the MMU or the CCU but I don't know yet what to do next. > http://u33i.imgup.net/groundstraebd1.gif Since the CCU is powered up and communicating with the buttons and indicators, it is likely OK. Since there was a big POP, and the CCU can't communicate with the MCU, which is where all the big power circuitry is, it seems REALLY likely something in the MCU popped. When you get it out, I think you are likely to find visible damage.   Jon

Danny DiAmico <dannydiamico@yahoo.com>: Apr 26 09:45AM On Tue, 26 Apr 2016 09:40:42 +0000, Danny DiAmico wrote:   > dark when nobody was in there (even then, we were aware someone could > be hurt but we didn't worry about it because we associated the darkness > with nobody being in there). < yes, we were kids >   PS: Don't remind me the time we took nitric acid, as I recall, and poured it into beakers containing iodine crystals and then dried it with either ether or alcohol (as I recall) and then painted anything we wanted e.g., the chemistry lab countertops, with the wet (stable) nitrogen tri-iodide paste.   When that stuff dries, it's so unstable, even a fly landing on it will cause it to explode (little purple cloud bursts sporadically popping all over the place!).   < yes, we were kids once >

Danny DiAmico <dannydiamico@yahoo.com>: Apr 26 09:40AM On Mon, 25 Apr 2016 21:53:48 -0700, Charles Bishop wrote:   > Why were the outlets and the lights on the same circuit?   I don't remember if it was one switch or two. I remember that the switch was just inside the doorway to the lab. So, it was usually turned on by the first person who entered the lab.   The lab itself had these long countertops down the length of the lab. At about eye level were the outlets. The caps we stuck in the outlets and I "do" remember the labs being dark when nobody was in there (even then, we were aware someone could be hurt but we didn't worry about it because we associated the darkness with nobody being in there). < yes, we were kids >

N_Cook <diverse@tcp.co.uk>: Apr 26 08:14AM +0100 On 26/04/2016 00:26, Michael Black wrote: > seem to recall trying the thing with alkaline AAs, and it was easier to > close that cover.   > Michael   The closers are Dzus Camlock. Perhaps deliberately undersized bores so as to lock you in to buying Garmin undersize AA batteries. If you are forcing home the closer , then you will have the same problem of the lower cells jammed in the bore. As the moulding around the bores is highly asymetric, perhaps the plastic releives over time and bends, anyway my "reaming" has done the trick, crude but effective, GPS still works BTW

Jon Elson <elson@pico-systems.com>: Apr 30 01:11PM -0500 Ralph Mowery wrote:     > Does the flux in solder really get old ?   Certain formulas definitely CAN! Also, the outside of the solder wire slowly accumulates more oxide, making the flux's job harder. > an expiration date on them of about a year and some want to be kept in > the refrigerator when not being used. Also bought some liquid flux and > it mentions an expiration date about a year or so later.   Paste has a lot of other properties than just flux. It has to spread through the solder stencil, leave nice "bricks" that don't slump, then do the flux job during reflow, and then either be washed off or not cause problems if the "no clean" type. A lot of jobs for one material.   If you let it sit at room temp for too long, it separates, and has to be remixed. > lots of things have an expired or use by date on them,but that does not > really mean much. I think the government just requires a date on some > items. I have had paste go bad on me, started to look like tiny cottage cheese in the jar, and didn't reflow well when used on a board. I added liquid flux to it, but that only helped a little. So, I had to get new stuff.   Jon

Adrian Caspersz <email@here.invalid>: Apr 30 06:57PM +0100 On 12/04/16 20:36, Ian Field wrote:   > Apparently that machine needs an ACHI driver which is absent from XP.   Yup, you'll need F6 drivers from their support site.   http://www.prime-expert.com/articles/b02/installing-windows-xp-with-f6-ahci-raid-drivers-from-usb-only.php   Or, if you go into the BIOS, you'll find a setting to enable SATA IDE Emulation mode. Then you can install XP directly.   Preferably something else though. If not Linux, Windows 7 might be certainly worth a go.   -- Adrian C

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